KUALA LUMPUR (Reuters) - Malaysia ordered 111 schools to close on Thursday as more than 200 children, teachers and others were taken to hospital after breathing in chemical fumes, but Prime Minister Mahathir Mohamad said he believed the poisoning crisis was under control.

A total of 250 people have been hospitalized, including eight in intensive care, according to the national disaster management agency, after being poisoned by fumes from chemical waste dumped in a river in the industrial district of Pasir Gudang in southern Johor state.

It was a sharp increase from the 35 people, mostly pupils, who were taken to hospital after the toxic waste dump was first detected last week.

“I think the situation is under control,” Mohamad told reporters in Pasir Gudang, after visiting the disaster management operation center and the hospital where the victims are being treated.

“The main thing is that even if there is a recurrence of other people getting affected... I think the people tasked with dealing with this problem, they know their way about and know how to control this unusual poisoning by gas.”

Mahathir said the outbreak did not merit a declaration of emergency and said that the government has deployed the necessary assets and expertise to deal with “whatever situation that happens”.

Earlier on Thursday, the armed forces sent 12 squadrons from its chemical, biological, radiological and nuclear unit to help clean up the toxic waste.

The government told parliament that it will inspect all 254 chemical plants operating in Pasir Gudang within three days in the hunt for those responsible.